First paragraph:
Which parties, if any, in a multiparty system have to be
considered as key players in the legislative game? Many
coalition theories define key parties that have superior
power in terms of coalition formation. Peleg's (1981)
dominant player, for instance, should become a member of the
government because of his seat strength in parliament,
whereas the central player (van Deemen, 1991; van
Roozendaal, 1993) holds a pivotal position due to the
inclusion of the median legislator. However, nothing is said
about the bargaining power of such key coalition game
players. Do such parties assert their policy and office
preferences better than their coalition partners do? And,
furthermore, does capturing a surpassing share of offices
imply that this party also has a strong showing for
implementing its policy preferences? In this article, a
modification of two seminal models - the portfolio
allocation model (Laver and Shepsle, 1990, 1996) and the
political heart model (Schofield, 1986, 1993, 1995, 1996) -
is used to define key players in the coalition game.
Building on this definition of key players, the office and
policy assertion capacity of such key parties in coalition
governments is evaluated, first, by looking at the share of
cabinet offices each party actually gets. Second, the policy
positions of pre-electoral party manifestos are contrasted
with those of post-electoral coalition agreements. The
results suggest that key parties indeed have more capacity
to assert their policy preferences than the remaining
parties in a coalition government. In terms of offices,
however, key players have not been able to capture a
disproportionate share of cabinet offices.

Figures and
Tables:

Figure 1. Two ideological party constellations with
and without a strong party

Figure 2. Example of a political heart (Belgium
1978

Table 1. Covered government formations and number of
analysed policy documents

Table 2. Evaluation of the modified strong party and
heart solution regarding coalition formation (predictions
in line with the model

Table 3. Office and policy payoffs of modified strong
parties when participating in a coalition government

Table 4. Party closest to the coalition agreement by
strong and large parties

Table 5. Office and policy payoffs of parties in the
modified heart solution

First paragraph of
Conclusion:
In this article, I have used the portfolio allocation and
political heart models to define key players in the
coalition game. The expectation is that a key player should,
first, become a member of the next government and, second,
should receive a surpassing share of office goods and have
more influence on policy. While the modified strong party
concept allows only for predictions whether a strong player
exists, which was the case in 28 of the 39
government-formation processes covered here, the modified
heart solution enables estimation of the composition of the
next government in all cases. Furthermore, while the
predicted modified strong party did not always become a
member of the next government, the modified heart solution
correctly predicted the partisan structure of the future
(coalition) government in all cases.